Try to make something like this? you can build it with Lego or try some books? Image
Otherwise I would tape the camera also to a high place, maybe the ceiling? lol
Try using a Tripod the cheapest where i live is $17 or like Seydie says stack books though if i had to use a phone or cheap camera to record something at a high place i would get creative
Depending on what console you're capturing from, if you're gonna spend $17 on a tripod you might as well just get an SD capture card for like $20: http://a.co/d/8cbgwoI (there are other, cheaper models, even going as low as $10 like here: http://a.co/d/9xFXeUu )
And most of the people who had issues with both of those cards were probably caused by the bad included software. Which you should almost never use to begin with.
Pretty much all consoles before the latest 3; PS4, Xbox One and Switch have the means to be captured through SD capture. I've fairly sure PS4 and Xbox One can also stream directly to Twitch through their on-board Twitch app. Switch is pretty much the odd one out. Thanks Nintendo.
I too have some pretty severe budget requirements but I recently did construct a low cost Standard Def speedrunning setup. Maybe this will help...
I use an AVerMedia EZMaker 7 which you can usually find for about $30 in the US, but I'm not sure how available it is in your locale, Brazil. It has composite and S-Video, and for me, works flawlessly over a standard USB 2 connection. My computer is 7 years old too, so it's no spring chicken on that side of things. I use S-Video, but some console S-Video cables are pretty expensive these days, ranging from 20 to 50 bucks USD on some, assuming you can find them. I was lucky to have bought a few of them back when I purchased my consoles, and while the quality is nice, it's certainly not necessary.
The PS3 should have come with a composite cord though (the Yellow, Red, and White RCA connection), assuming they didn't take that out of the package in later revisions. PS3's composite really isn't terrible too, compared to some other consoles, and certainly more than serviceable for speedruns!
If you can find one and afford it, try it out! Might work nice for you as well.
Here's an Amazon link with some info, it's not for your location, but it might help: https://www.amazon.com/AVerMedia-Definition-Composite-Cyberlink-C039/dp/B00603S1OS
I should also mention that this card is pretty much plug and play with OBS. You can just install the driver and ignore all the software it comes with.
I used a similar setup in the past with an easy cap. It certainly works (particularly with retro consoles, with newer ones I haven't tested) and cost about $20 to get it up and running.